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Implement debugging with TXT records

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Signed-off-by: Miek Gieben <miek@miek.nl>
This commit is contained in:
Miek Gieben
2020-03-06 09:13:27 +01:00
parent deb582259a
commit b00ff13ca0
6 changed files with 64 additions and 38 deletions
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29
plugin/traffic/traffic.go
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@@ -13,6 +13,7 @@ import (
"github.com/coredns/coredns/plugin/traffic/xds"
"github.com/coredns/coredns/request"
corepb "github.com/envoyproxy/go-control-plane/envoy/config/core/v3"
"github.com/miekg/dns"
)
@@ -25,7 +26,6 @@ type Traffic struct {
hosts []string
id string
health bool
origins []string
Next plugin.Handler
@@ -48,7 +48,8 @@ func (t *Traffic) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg
m.SetReply(r)
m.Authoritative = true
sockaddr, ok := t.c.Select(cluster, t.health)
healthy := state.QType() == dns.TypeTXT
sockaddr, ok := t.c.Select(cluster, healthy)
if !ok {
// ok this cluster doesn't exist, potentially due to extra labels, which may be garbage or legit queries:
// legit is:
@@ -69,14 +70,14 @@ func (t *Traffic) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg
if strings.HasPrefix(strings.ToLower(labels[0]), "endpoint-") {
// recheck if the cluster exist.
cluster = labels[1]
sockaddr, ok = t.c.Select(cluster, t.health)
sockaddr, ok = t.c.Select(cluster, healthy)
if !ok {
m.Ns = soa(state.Zone)
m.Rcode = dns.RcodeNameError
w.WriteMsg(m)
return 0, nil
}
return t.serveEndpoint(ctx, state, labels[0], cluster)
return t.serveEndpoint(ctx, state, labels[0], cluster, healthy)
}
case 3:
if strings.ToLower(labels[0]) != "_grpclb" || strings.ToLower(labels[1]) != "_tcp" {
@@ -88,7 +89,7 @@ func (t *Traffic) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg
// OK, _grcplb._tcp query; we need to return the endpoint for the mgmt cluster *NOT* the cluster
// we got the query for. This should exist, but we'll check later anyway.
cluster = t.mgmt
sockaddr, _ = t.c.Select(cluster, t.health)
sockaddr, _ = t.c.Select(cluster, healthy)
break
default:
m.Ns = soa(state.Zone)
@@ -120,7 +121,7 @@ func (t *Traffic) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg
}
m.Answer = []dns.RR{&dns.AAAA{Hdr: dns.RR_Header{Name: state.QName(), Rrtype: dns.TypeAAAA, Class: dns.ClassINET, Ttl: 5}, AAAA: sockaddr.Address()}}
case dns.TypeSRV:
sockaddrs, _ := t.c.All(cluster, t.health)
sockaddrs, _ := t.c.All(cluster, true)
m.Answer = make([]dns.RR, 0, len(sockaddrs))
m.Extra = make([]dns.RR, 0, len(sockaddrs))
for i, sa := range sockaddrs {
@@ -136,6 +137,18 @@ func (t *Traffic) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg
m.Extra = append(m.Extra, &dns.A{Hdr: dns.RR_Header{Name: target, Rrtype: dns.TypeA, Class: dns.ClassINET, Ttl: 5}, A: sa.Address()})
}
}
case dns.TypeTXT:
sockaddrs, _ := t.c.All(cluster, false)
m.Answer = make([]dns.RR, 0, len(sockaddrs))
m.Extra = make([]dns.RR, 0, len(sockaddrs))
for i, sa := range sockaddrs {
target := fmt.Sprintf("endpoint-%d.%s.%s", i, cluster, state.Zone)
m.Answer = append(m.Answer, &dns.TXT{
Hdr: dns.RR_Header{Name: state.QName(), Rrtype: dns.TypeTXT, Class: dns.ClassINET, Ttl: 5},
Txt: []string{"100", "100", strconv.Itoa(int(sa.Port())), target, corepb.HealthStatus_name[int32(sa.Health)]}})
m.Extra = append(m.Extra, &dns.TXT{Hdr: dns.RR_Header{Name: target, Rrtype: dns.TypeTXT, Class: dns.ClassINET, Ttl: 5}, Txt: []string{sa.Address().String()}})
}
default:
m.Ns = soa(state.Zone)
}
@@ -144,7 +157,7 @@ func (t *Traffic) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg
return 0, nil
}
func (t *Traffic) serveEndpoint(ctx context.Context, state request.Request, endpoint, cluster string) (int, error) {
func (t *Traffic) serveEndpoint(ctx context.Context, state request.Request, endpoint, cluster string, healthy bool) (int, error) {
m := new(dns.Msg)
m.SetReply(state.Req)
m.Authoritative = true
@@ -167,7 +180,7 @@ func (t *Traffic) serveEndpoint(ctx context.Context, state request.Request, endp
return 0, nil
}
sockaddrs, _ := t.c.All(cluster, t.health)
sockaddrs, _ := t.c.All(cluster, healthy)
if len(sockaddrs) < nr {
m.Ns = soa(state.Zone)
m.Rcode = dns.RcodeNameError